This app was mentioned in 2 comments, with an average of 2.00 upvotes
I removed almost all of the games off of my phone, but I've been playing a bit of Byte Master every once in a while. It's the same idea as 2048 where you slide panels together and matching panels merge, but you get bytes/kilobytes/etc that you can then spend on idle-styled upgrades such as how many bytes a second you earn and how long they'll collect for you offline.
As you advance through the levels, you unlock powers such as Undo, Erase a tile, Double a value, etc. You earn Coins by doing missions and you can apparently pay to get more, but you also get an increasing number of Coins for playing consecutive days. Coins are then used to buy/upgrade new gadgets or to unlock powers before their natural unlock. It's playable entirely offline too!
A tip is that when you lock the board and have zero moves, you're forced to either wait quite a while to save your accumulated bytes, watch a video ad, or you can restart but lose all of them--it might be worthwhile to burn all of your bytes on upgrades one move before failure, lock the board, and then restart. The idle timer seems to replenish one minute for every one second of real time you have the app open, so if you have a timer of 3h 30m, you'd need to keep it open for three and a half minutes to fully restore it. And of course you can play while this is going on.
2048 IDLE is largely the same thing but there's a bug where the sound defaults to on regardless of what you set it to the last time you played.